Grinding machine



ttorrieg.

March 2, 1937. H. G. DAY

GRINDING MACHINE Filed May 17; 1933 Patented Mar. 2, 1937 UNITED STATES ATENT OFFICE 10 Claims.

This invention relates to a grinder which can be employed to reduce or pulverize various materials, but which has been designed to be more especially useful to reduce or pulverize grain.

A broad object of the invention is to provide a grinder or grinding machine of the closed system type wherein will be incorporated various novel and improved features and characteristics ci construction designed to render the present grinder or grinding machine an improvement generally over more or less similar structures heretofore known.

A more explicitly stated object is to provide a grinder or grinding machine including closed system conveyors for moving a column of air and ground material transported by said moving column of air, wherein said conveyors will be so constructed and related to each other, and to the grinding element, the ian or blower and the collector o the grinder or grinding machine, that the reducing or pulverizing action upon the material being ground and the conveying of the ground material to the receiver therefor will be accomplished in really ideal manner, without liability of loss of any of the ground material,

in the form of dust, or otherwise, from the grinder or grinding machine or any of the conveyors thereof.

A further explicitly stated object is to provide a grinder or grinding machine including closed system conveyors for the purpose and of the construction and having the relation to each other and to the grinding element, the fan or blower and the collector of the grinder or grinding machine as set forth, wherein all of the component parts oi said grinder or grinding machine have been designed with the idea in View of nicely controlling the amount, velocity and pressure of air of the moving column at the various locations in the grinder or grinding machine, and especially at and adjacent to the grinding element, the fan or blower, the co1lector, and the receiver for the 'ground material, to thus balance the grinding and air blowing condition in said grinder or grinding machine and reduce to a minimum the possibility of loss of the ground material, even in the form of dust.

And a further explicitly stated object is to Iprovide a. closed system grinder or grinding machine, the air and ground material transporting conveyors of which are so constructed and related to each other, and to all other component parts of the grinder or grinding machine, that /tendency of air to enter said system or become removed therefrom is reduced to a minimum, once the grinder or grinding machine is set in operation.

With the above objects in View, as well as others which will appear as the specification proceeds, the invention comprises the construction, arrangement and combination of parts as now to be fully described and as hereinafter to be speciiically claimed, it being understood that the disclosure herein is merely illustrative and intended in no way in av limiting sense, changes in details of construction and arrangement of parts being permissible so long as within the spirit of the invention and the scope of the claims which follow.

In the accompanying drawing forming a part of this specication,

Fig. 1 is an elevational view, partially in section and partially broken away, of a grinder or grinding machine in which the features of the invention are incorporated;

Fig. 2 is a fragmentary elevational view of the grinder or grinding machine, as seen from the right in Fig. l; and

Fig. 3 is a fragmentaryv plan view, as seen fromk the top of the sheet in Fig. l.

With respect to the drawing and the numerals of reference thereon, I denotes a casing for the grinding element of the grinder or grinding machine, and Ii indicates a casing for the fan or blower. As shown, said grinding element and said fan or blower are mounted adjacent each other upon a horizontal shaft I2. Said grinding element and said fan or blower are iixed to the shaft i2, and a pulley i3, also fixed to said shaft, may be suitably driven to propel the grinding element and fan or blower, although these may be propelled in any other suitable manner.

The grinding element casing I includes an open mouth I4 above the grinding element, and a bin spout or outlet, represented I5, leading from a supply of grain or other material to be reduced or pulverized, may enter directly into said mouth I4 of said casing I0.

The grinding element casing I0 includes a feed device I6 for grain orother material to be ground, and said feed device is actuated from the shaft I2 by means of a belt Il riding over a pulley I8 upon said shaft I 2.

A collector I9 for reduced or pulverized grain, or other reduced or pulverized material, is situated at elevation above the grinding element and the fan or blower, at one side of said element and ian or blower as disclosed, and a receiver 20 for said reduced or pulverized grain,

or other material, 4is arranged directly below said collector. As shown, the lower` portion 2I of said collector I9 is tapered to tightly t into an opening in the upper wall of the receiver 20, as indicated at 22, whereby the collector feeds directly into the receiver, as will be obvious. The receiver 2li can be a completely closed storage tank, except for the opening therein leading from the collector. As disclosed, the lower portion of the receiver is also tapered, as denoted at 23, and said tapered portion 23 merges into a downwardly extending outlet pipe 2li, of cross-sectional area considerably less than that of the receiver. The lower portion of said pipe 24 is fitted with a horizontal slidevalve 25 which can be completely closed, as shown in Fig. 1 of the drawing, or can be opened to allow passage by gravity of ground grain or other ground material into containers therefor, such, for example, as the sack 26 placed upon the table 27, beneath the pipe 24.

The grinder or grinding machine includes a conveyor 28 for reduced or pulverized grain or other material and air leading upwardly from the fan or blower casing II to the collector I9, and a conveyor 29 for air leading downwardly from said collector to the grinding element casing to either side of the grinding element and to said fan or blower casing, which conveyors 28 and 29 are so constructed and related to each other and to said grinding element, fan orblower and collector that the reducing or pulverizing action upon the material being ground and the conveying of the ground material to thek collector, and thence by gravity to the-receiver, is accomplished without liability of loss of ground material. That is to say, all of the component parts of the grinder or grinding machine, including the grinding element and its casing, the fan or blower and its casing, the collector, the receiver, and the conveyors 28 and 29, have been designed and constructed and related to each other with the idea in View of ynicely controlling the amount, velocity and pressure of air at the several different locations in the grinder or grinding machine, to thereby not only reduce to a minimum the tendency of air to enter or become removed from the grinding system of the machine and thus preclude the loss of ground material, but also to nicely balance the grinding and air blowing condition in the grinder or grinding machine.

The conveyor 28 is vertically disposed as shown, and includes an upper horizontal portion 3D which tangentially and tightly enters the upper portion of the vertical wall of the collector I9, as indicated at 3|.

The conveyor 29 includes an upper bent or curved portion 32 tightly fitted into the upper wall of the collector I9 and leading therefrom, -a-vertical portion 33 extending downwardly from said portion 32, a branch 34 which as disclosed extends obliquely downwardly from said vertical portion 33 and is tightly fitted into the grinding element casing IQ above the grinding element, and a branch 35 extending horizontally from said vertical portion 33 past the lower portion of the grinding element casing Ill and then bent or curved, as at 36, and tightly tted into the fan or blower casing II. The grinding element casing I il is tightly tted into and communicates with the branch 35 of the conveyor 29 at the side of the grinding element which is opposite the branch 34, as clearly indicated at 3l in Fig. l.

As will be evident, when the shaft I2 is driven to operate the grinding element and the fan or blower, air is fed to the grinding element casing and to the fan or blower casing, past the outlet 31 of said grinding element casing, through the conveyor 29 and the branches 3ft and 35 thereof. The reduced or pulverized material, which was fed into the casing I El through the mouth I4 thereof, is carried by the air past the outlet 3'! and through the branch S5 and its curved portion 36 to the fan or blower casing. The mixed air and ground material are then fed upwardly through the conveyor 28 and into the collector I9, where said air and ground materiai separate, the ground material falling by gravity through the collector i9 into the receiver 2B, and the airy with some lighter particles oi ground material, enters the curved upper portion 32 of the conveyor 29 and then passes downwardly through said conveyor 29 to repeat the cycle as described. Both the air which passes from the vertical portion 33 of the conveyor 29 through the branch 34 directly into the casing IS and the air which passes from said vertical portion through the branch 35 past the outlet 3l cooperate to carry the ground material to the ian or blower, as will be evident.

It will be noted that the portion of the conveyor 29 attached to the collector i9 and extending to position below the branch 3d is of considerably greater cross-sectional area than is the conveyor 28 leading from the ian or blower to said collector I9. For example, the mentioned portion of theconveyor 29 may desirably be, say, ten inches in diameter when the conveyor 28 is six inches in diameter, so that, the velocity and pressure of air in the portion of said con` veyor 29 extending from the collector i9 to the branch 94, or below said branch, will be relatively lower than the velocity and pressure of air in the conveyor 28, as will be understood. Thus the air can be led easily from the vertical portion 33 of the conveyor 29 into the branches Sli and 35, respectively, which branches may desirably each be of about the same cross-sectional area as is the conveyor 29.

While the velocity and pressure of air' in the portion of the conveyor 29 leading from the collector I9 down to the location of the outlet of the branch 34, and particularly adjacent said outlet, is relatively lower than the velocity and pressure of air in the conveyor 28, the amount of air in said mentioned portion of the conveyor 29 is always of suicient capacity so that each of the branches 34 and 35 can be supplied a' requisite quantity of air during the operation of the grinding element and the fan or blower.

More specically stated, the fan or blower builds up in the conveyor 28, along the whole of the length thereof, a velocity and pressure of air which becomes approximately fixed shortly after the fan or blower is set in operation, and thereafter remains substantially xed as long as the grinding operation continues. Evidently, the moving content in said conveyor 28 consists at all times of a considerable quantity of ground material in addition to the air. When the ground material becomes. separated from the air in the collector i9, the pressure of air entering the conveyor 29 is decreased, and air passing downwardly through the portion 33 of the conveyor 29 is under pressure lower than the pressure in the conveyor 28 and travels at slower velocity than the content of said conveyor 28. The air traveling at slow velocity and under low pressure and directly accessible to the branch 34, allows for easy leading of the air through said branch 34 into the grinder element casing,'which so takes all of the air necessary to the grinding operation as this progresses from time to time. The .remainder of the air passing through the conveyor 2.9 goes Yto the fan `or blower through the branch 35, past the outlet 31 from the grinding element casing l0, and the branches 34 and 35 cooperate to keep the air pressure in the upper portion of the conveyor 29 from rising to too high a. pressure.

In order that the grinding and air blowing condition in the grinder or grinding machine may be properly balanced, itis essential that each of the branches 34 and 35.1oe of suiiicient cross-sectional area so y'that either will have capacity to transport the major part of the air passing through the upper portion of the conveyor 29 to either side of the grinder proper. Were said upper portion of the conveyor 29 of cross-sectional area as small as, or not much greater than, the cross-sectional area. of each of the conveyor 28, the branch 34, and the branch 35, there would obviously be no capacity for feeding any considerable quantity of air through f said branch 34, for the reason that by far the greater part of the air traveling at relatively high velocity would pass through the branch 35 rather than through the branch 34, due both to the fact that the fast traveling, small amount of air is not easily leadable, and the further fact that the grinding operation itself sets up a certain amount of resistance to the air. And were the condition altered to reduce the amount of air which could possibly travel through the branch 35, there would then be, under certain working conditions, an unbalancing ofA the grinding and air Yblowing condition, because at times when the grinder proper gets choked, or partially choked, there must be full capacity for all of the air to travel through the branch 35 and past the outlet 3l. Upon the grinder proper becoming choked, or partially choked, there is in the machine capacity for passage of all of, or the greater part of, the air through the branch 35 and past the outlet 3l, where said air creates a suction action upon the grinder proper. In short, there is capacity for passage of air in considerable quantity through the grinder proper, as Well as capacity for passage of all of the air traveling through the upper portion of the conveyor 29 through the branch 35, and the component parts of the grinder or grinding machine are so constructed and related to each other that the air travel through said branches 34 and 35 is automatically varied and controlled as the machine operates, to insure that the grinding and the air blowing condition will at all times remain properly balanced.

The grinder or grinding machine includes an air bleeder pipe 38 which leads upwardly from the upper wall of the receiver 2Q, is bent or curved horizontally and then obliquely downwardly, and is tightly attached, as at 39, to the vertical portion 33 of the conveyor 23, at location above the branch 34. 'Ihe evident purpose of the pipe 38 is to carry any traces of air which may enter the receiver 29 with ground grain, or

other ground material, directly into the conveyor 29.

It will vbe seen that the flow of air in the grinder or grinding machine is continuous, and the same air. There is no tendency for air to enter the casing I0 with the grain to be ground, principally for the reason that the full need for air in the grinder proper is adequately supplied throughlthe branch 34, .as Yalready set forth. There is, ialso, no air outlet to carry nparticles or dust away from the Iground material. The only outlet from the machine Yis the .pipe 24, which can, as before stated,'befcompletely closed. And even when the pipe 24 vis opened, the ground grain, or other ground material, passing downwardly therethrough provides a seal against ythe passage of air upwardly through said `pipe 24 to the receiver.

What is claimed is:

1. A grinding machine comprising .a grinding element, a casing for said grinding element, a blower, a casing for said blower, a collector for ground material above said blower, a conveyor for air and ground material kleading upwardly from said blower casing to said collector, and a conveyor for air leading Idownwardly from said collector and including branches one of `which feeds into said grinding element casing and the other of which feeds into said blower casing at the side thereof opposite said first mentioned conveyor, said grinding element casing opening to said branch feeding into said blower casing at the side of said grinding element opposite said branch feeding into said grinding element casing, and the portion of said air conveyor between said collector and said branch feeding into said grinding element casing being of suihciently great capacity to transport air at velocity and under pressure lower than the Velocity at which and the pressure under which air and ground material are transported by said air and ground material conveyor.

2. A grinding machine comprising a grinding element, a casing for said grinding element, a blower, a casing for said blower, means for operating said grinding element and said blower, a

collector for ground material, a conveyor for air and ground material leading from said blower casing to said collector, and a conveyor for air leading from said collector and including branches one of which feeds into said grinding element casing andthe other of which feeds into said blower casing at the side thereof opposite said first mentioned conveyor, said grinding element casing opening to said branch feeding into said blower casing at the side of said grinding element opposite said branch feeding into said grinding element casing, and the portion of said air conveyor between said collector and said branch feeding into said grinding element casing being of greater cross-sectional area than the cross-sectional area of said air and ground material conveyor.

3. A grinding machine comprising a grinding element, a casing for said grinding element, a blower, a casing for said blower, means for operating said grinding element and said blower, a collector for ground material, a conveyor for air and ground material leading from said blower casing to said collector, and .a conveyor for air leading from said .collector and including branches one of which feeds into said grinding element casing at the side thereof where material to be ground enters said casing and the other of which feeds into said blower casing at the side thereof opposite said rst mentioned conveyor, the side of said grinding element casing where ground material departs opening'tosaid branch feeding into said blower casing, said conveyor for air and ground material, and said branches, respectively, being of approximately equal crosssectional area, and the portion of said conveyor for air between said collector and said branches being of considerably greater cross-sectional area than the cross-sectional area of said conveyor for air and ground material, or either of said branches, for the purpose described.

4. The combination as specified in claim 3, wherein said portion of said conveyor for air between said collector and said branches is of cross-sectional area at least one and one-half times as great as the cross-sectional area of said conveyor for air and ground material, or either of said branches.

5. A grinding machine comprising a grinding element, a casing for said grinding element, a blower, a casing for said blower, a collector for ground material, a conveyor for air and ground material between said blower casing and said collecto-r, and a conveyor for air between said collector and said grinding element casing and said blower casing, said last mentioned conveyor including a branch leading into and a branch leading away from said grinding element casing, and also including a portion. thereof adjacent said branch leading into said grinding element casing of capacity necessitating air to pass through said portion at relatively lower pressure than air and ground material pass through said first mentioned conveyor.

6. A grinding machine comprising a grinding element, a casing for said grinding element, a blower, a casing for said blower, a collector for ground material, a conveyor for air and ground material leading from said blower casing to said collector, and a conveyor for air leading from said collector and including a branch leading into said grinding element casing and a branch leading into said blower Casing, a portion of said last mentioned conveyor adjacent said branch leading into said grinding element casing being of capacity necessitating air to travel therein at relatively lower velocity and pressure than air and ground material travel through said first mentioned conveyor.

7. A grinding machine comprising a grinding element, a casing for said grinding element, a blower, a casing for said blower, a collector for ground material, a conveyor for air and ground material between said blower casing and said collector, a Conveying passage for air leading from said collector and of sufcient capacity to cause air to travel therein at velocity less than that at which air and ground material travel in said conveyor between said blower and collector, a branch passage leading from said conveying passage into said grinding element casing at the side thereof which receives material to be ground, and a branch passage leading from said conveying passage to said blower casing, the side of said grindinfT element casing where ground material departs communicating with said last mentioned branch passage, and each of said branch passages being of sufficient capacity to alone transport in the machine the major portion of the air which passes through said conveying passage.

8. A grinding machine comprising a grinding element, a casing for said grinding element, a blower, a casing for said blower, a collector for ground material, a conveyor for air and ground material lea-ding from said blower casing to said collector, and a conveyor for air leading from said collector and including branches one of which feeds into said grinding element casing at the inlet side thereof and the other of which feeds into said blower casing, said grinding element casing opening at the outlet side thereof to said branch feeding into said blower casing, a portion of said conveyor for air between said collector' and said branch feeding into said grinding element casing having area to transport air at relatively lower velocity than the velocity at which air and ground material are transported by said conveyor for air and ground material, and each of said branches being related to said mentioned portion of the conveyor for air and having capacity to transport a requisite amount of air from said portion to the grinding element casing and the blower casing, respectively, to at all times balance the grin-ding condition in the grinding element casing and thus reduce to a minimum the possibility of loss of ground material.

9. A grinding machine comprising ra grinding element, a casing for said grinding element, a blower, a casing for said blower, a collector for ground material, a conveyor for air and ground material between said blower casing and said collector, a conveying passage for air leading from said collector and of suiicient capacity to cause air to travel therein at velocity less than that at which air and ground material travel in said conveyor between said blower and said collector, a branch passage leading from said conveying passage into said grinding element casing at the side thereof which receives material to be ground, and a branch passage leading from said conveying passage to said blower casing, the side of said grinding element casing where ground material departs communicating with said last mentioned branch passage, each of said branch passages having capacity to transport a requisite amount of air from said conveying passage to said grinding element casing and said blower casing, respectively, to balance the grinding condition in said grinding element casing, and said branch passages cooperating with each other to keep the air pressure uniform in said conveying passage.

10. A grinding machine comprising a grinding element, a casing for said grinding element, a blower, a casing for said blower, a collector for ground material, a conveyor for air and ground material between said blower casing and said collector, and a conveyor for air between said collector and said grinding element casing and said blower casing, said last mentioned conveyor including a branch leading into said grinding element casing and a branch leading into said blower casing at a side thereof opposite said rst mentioned conveyor, said grinding element casing opening to said branch leading into said blower casing at the side of said grinding element opposite said branch leading into said grinding element casing, and a portion of said conveyor for air adjacent said branches leading into said grinding element casing and said blower casing, respectively, being of capacity necessitating air to pass through said portion at relatively lower velocity and pressure than air and ground material travel through said rst mentioned conveyor.

HARRY G. DAY. 

